It is generally well known that valves are important devices for the regulation of the flow of fluids in pipes or other such conduits. As known to those skilled in the art, a valve regulates the rate of fluid flow as the position of the valve plug within the valve is changed by an actuator. Two important features of a valve, such as a globe valve, are that it is generally desirous to be able to fully stop the flow fluid at the closed position and be capable of withstanding the temperatures and chemical influences of the fluid flowing therethrough. In order to properly stop the flow of fluid, it is advantageous for the mating surfaces within the valve to engage with a relatively high degree of precision. Even with this relatively high degree of precision, valves typically include elastomeric seals such as, washers, O-rings or the like to ensure a fluid-tight seal when the valve is positioned in a closed configuration. Typical globe valves are used in numerous applications ranging from simple level control to boiler feed water systems, superheated bypass applications, control of radioactive fluids, caustic or acidic fluids, and the like. Unfortunately, elastomeric materials are not capable of withstanding some of these relatively extreme conditions. In addition, large globe valves such as those having a flow control orifice or port greater than 6-inches in diameter and are known to suffer from seal failures.
Unfortunately, it is difficult to provide a seal that functions across a range of pressures and temperatures, that is compatible with a variety of fluids, that allows the valve to be opened and closed with minimal effort, and that is sufficiently wear resistant to withstand repeated opening and closing operations. While these issues are historically well known, conventional valves still suffer from one or more of these disadvantages.
Accordingly, it is desirable to provide a valve that overcomes the disadvantages described herein at least to some extent.